In designing today's modern computing centers for digital computer and their associated equipment, i.e., I/O's, printers, modems, etc., architects provide a rather standard approach to construction: a sub-floor say of concrete is first poured and then a raised support floor is built above the sub-floor. The latter usually consists of a series of horizontal panels removably resting on a web of rails supported, in turn, by a set of headers. A vertical workspace is provided between the panels and the sub-floor in order to stow electrical wiring harnesses and the like, to permit easy internal connection of the computer and associated peripheral equipment as well as external connection of the latter to outside tieing equipment.
Since such centers represent a large capital investment, a detection system is typically provided to warn operators if water enters the sub-floor beneath the computing equipment. The system usually includes a detector subassembly consisting of a fabric mesh of electrically inert material supporting a pair of electrical conductors.
The subassembly is placed atop the concrete sub-floor in a predetermined deployment pattern. Electrically, the conductors connect to a display panel through a controller.
If water comes into contact with the fabric mesh, an electrical circuit that includes the conductors, the water bridge and an energy source (at the controller), is closed. At the display panel, a visual and/or audio alarm in the same circuit become energized, alerting the operator to the presence of water (at the floor level below the computing equipment).
But experience has now shown that during frequent renovation, repair or replacement of the computer and/or associated equipment, workmen laboring in the work space, can abuse the fabric mesh atop the sub-floor, resulting in unreliable operations of the water detection system.
That is to say, the activity of the workmen, e.g., can roughen the fabric mesh allowing the latter to loosen its fit about the conductors. Since the relative distance between conductors is thus altered (sometimes drastically!), the amount of water that activates the system is likewise changed but in a non-linear manner. The resulting unreliability inherent in such circumstances, can be very disruptive to normal operations, especially in the environment of a busy computing center in which various computing and associated activities are occurring simultaneously.